Materials Transactions, Vol.45 No.04 (2004) pp.1395-1399
© 2004 The Japan Institute of Metals

Glass Forming Ability and Mechanical Properties of Misch Metal-Based Bulk Metallic Glass Matrix Composite

Ji-Hun Kim¹, Joo Yun Lee¹, Jin Man Park¹, Eric Fleury², Won Tae Kim³ and Do Hyang Kim^1,

The effect of replacement of lanthanide by misch metal (Mm) in La-Al-TM (TM; transition metal, Ni, Cu and Co) alloys has been investigated to evaluate the possibility of fabrication of in-situ glass matrix composites with enhanced properties. For the as-cast cylindrical Mm₅₅Al₂₅Ni₁₀Cu₁₀ alloy ingot with 3 mm diameter, the microstructure is consisted of two kinds of a few μm size crystalline phases (volume fraction: 4.6%) uniformly distributed in the metallic glass matrix. The substitution of La by Mm reduces the glass forming ability (GFA), i.e., lower the reduced glass transition temperature, T_rg (= T_g / T_L, where T_L is the liquidus temperature) and smaller superliquid temperature region, Δ T_x (= T_x - T_g, where, T_g is the glass transition temperature and T_x the onset temperatures of crystallization), enabling the fabrication of in-situ BMG matrix composite. The Mm₅₅Al₂₅Ni₁₀Cu₁₀ metallic glass matrix composite sample exhibits the compressive fracture strength of 931 MPa, and in particular enhanced the compressive plastic strain of 1.2% before failure. The enhanced strength and ductility was explained by the presence of fine crystalline phases embedded in the BMG matrix, which led to a multiple shear band formation.

(Received 2003/11/25; Accepted 2004/3/12)

Keywords: bulk metallic glass composite, glass forming ability, misch metal base alloy

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